Heat storage due to photosynthesis and respiration activities in forests

This study evaluated heat storage flux or released flux due to biotic activity (S_C) in forests. First, as a case study, we investigated diurnal pattern of S_C over an evergreen coniferous forest via a three-year continuous eddy-cov riance CO₂ flux measurement. We clarified that (1) in some case, SC reached over 15% of total heat storage flux during the snow-free period (May-October), (2) S_C was 4.3 W m^-2 on average and reached 4.9-7.0% of average sensible and latent heat fluxes during the snow-free period. Second, we estimated S_C by using net ecosystem exchange over several forest ecosystems as reported by previous studies. During the snow-free period over several forest ecosystems, the maximum S_C and daily amplitude exceed 3-12 and 4-17 W m^-2 respectively. Those values were comparable to those of the latent heat storage flux in the air layer from the ground surface to the level of eddy-covariance measurement over several forest ecosystems as shown by previous reports. Our findings suggest that S_C cannot be always ignored. We would need to examine whether S_C can be ignored based on the circumstances of the targeted research.